The invention relates to a low-pressure mercury vapor discharge lamp comprising a discharge vessel,
which discharge vessel encloses a discharge space containing a filling of mercury and an inert gas in a gastight manner, PA1 an electrode being arranged at each end portion in the discharge space for generating and maintaining a discharge in the discharge space, PA1 current supply conductors of the electrodes extending through the end portions so as to project from the discharge vessel, PA1 and at least one of the current supply conductors carrying an amalgam.
In mercury-vapor discharge lamps, mercury constitutes the primary component for (efficiently) generating ultraviolet (UV) light. An inner wall of the discharge vessel may be coated with a luminescent layer comprising a luminescent material (for example a fluorescent powder) for converting UV light to other wavelengths, for example UV-B and UV-A for tanning purposes (sunbed lamps) or to visible radiation. Such discharge lamps are therefore also referred to as fluorescent lamps.
A low-pressure mercury vapor discharge lamp of the type mentioned in the opening paragraph is known from U.S. Pat. No. 4,105,910. In the known discharge lamp, the current supply conductor carries an amalgam which is provided on a metal plate which is secured to the current supply conductor. This amalgam acts as an auxiliary amalgam and serves to increase the run-up rate, that is the rate at which the discharge lamp approximates its rated light intensity after having been switched on. This is achieved by the fact that, after switching-on the lamp, heat originating from the electrode causes the amalgam to give off the mercury bonded thereto, thereby causing the mercury vapor pressure in the discharge vessel to increase to a value which is desired for nominal operation. This has the drawback, however, that the plate entails extra costs due to its manufacture, storage, transport and assembly with other parts of the discharge lamp.